sneaker

名词 sneaker:

1. a canvas shoe with a pliable rubber sole
   同义词：gym shoe, tennis shoe
2. someone acting as an informer or decoy for the police
   同义词：fink, snitch, snitcher, stoolpigeon, stool pigeon, stoolie, sneak, canary

形容词 sneak:

1. marked by quiet and caution and secrecy; taking pains to avoid being observed
   同义词：furtive, sneak, sneaky, stealthy, surreptitious